oxalic acid

The Columbia Encyclopedia, 6th ed.

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oxalic acid (ŏksăl´Ĭk) or ethanedioic acid (ĕth´āndīōĬk), HO2CCO2H, a colorless, crystalline organic carboxylic acid that melts at 189°C with sublimation. Oxalic acid and oxalate salts are poisonous. Oxalic acid is found in many plants, e.g., sorrel and rhubarb, usually as its calcium or potassium salts. Oxalic acid is the only possible compound in which two carboxyl groups are joined directly; for this reason oxalic acid is one of the strongest organic acids. Unlike other carboxylic acids (except formic acid), it is readily oxidized; this makes it useful as a reducing agent for photography, bleaching, and ink removal. Oxalic acid is usually prepared by heating sodium formate with sodium hydroxide to form sodium oxalate, which is converted to calcium oxalate and treated with sulfuric acid to obtain free oxalic acid.

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oxalic acid

oxalic acid A dicarboxylic acid, chemically COOH—COOH. Poisonous in large amounts; present especially in spinach, chocolate, rhubarb, and nuts. The toxicity of rhubarb leaves is due to their high content of oxalic acid.

High concentrations of oxalates in the urine can form kidney stones; while most of these oxalates are of endogenous metabolic origin, patients with hyperoxaluria are advised to avoid dietary sources of oxalates.

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oxalic acid

oxalic acid (oks-al-ik) n. an extremely poisonous acid found in many plants, including sorrel and the leaves of rhubarb, and in some bleaching powders. When swallowed it produces burning sensations in the mouth and throat, vomiting of blood, breathing difficulties, and circulatory collapse. Treatment is with calcium lactate or other calcium salts, lime water, or milk. Formula: C2H2O4.

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oxalic acid

oxalic acid (C2H2O4) Poisonous, colourless crystalline organic acid whose salts occur naturally in some plants, such as sorrel and rhubarb. It is used for metal and textile cleaning and in tanning. Properties: m.p. 101.5°C (214.7°F).

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oxalic acid

oxalic acid (ethanedioic acid) A crystalline solid, (COOH)2, that is slightly soluble in water. Oxalic acid is strongly acidic and very poisonous. It occurs in certain plants, e.g. sorrel and the leaf blades of rhubarb.

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